This chromium nickel molybdenum alloy is a widely used deep-hardening constructional steel. It is used at a variety of strength levels and at each level possesses remarkable ductility and toughness. With its high alloy content uniform hardness is developed by heat treatment in relatively heavy sections. High fatigue strength makes E-4340 ideal for highly stressed parts. It maintains its strength and hardness at elevated temperatures.

This grade is available as electric furnace vacuum degassedmore
Unit of Measure

Specifications

Estimated Weight per Foot

12.76 lb

Estimated Weight 12-Ft. Bar

153.1 lb

Analysis

N/A Carbon .38/.43
Manganese .65/.85
Phosphorus .025 Max.
Sulphur .025 Max.
Si. .15/.30
Cr. .70/.90
Ni. 1.65/2.00
Mo. .20/.30

Applications

N/A Intended for parts with sections 3 1/2" or less in thickness at time of heat treatment, which require a through-hardening steel capable of developing minimum hardness of Rockwell "C" 30.
Premium Aircraft Quality is intended for use in the manufacturing of highly stressed parts at higher strength levels, such as 260/280,000 psi and where a much cleaner steel is desired.

Hardening

N/A End-quench hardenability values for this grade are Rockwell "C" 50 minimum at 20/16" and Rockwell "C" 45 minimum at 3 2/16"

Heat Treating

N/A Normalize—1650°F
Austenitize—1500°F
Quench—Oil, 140 °F maximum

Temper—400/500°F for 260,000 psi strength level
725°F minimum for lower strength levels